1. Field
Methods and apparatuses consistent with the exemplary embodiments relate to a luminescence driving apparatus, a display apparatus, and a driving method thereof, and more particularly, to a luminescence driving apparatus which can perform an overvoltage protection (OVP) function with respect to each channel, and a display apparatus, and a driving method thereof.
2. Description of the Related Art
With the development of slimmer display devices, an edge-lit type light-emitting diode back light unit (LED BLU) has been actively developed. Since driving a plurality of LEDs, which are connected to one another in series, using one driving circuit is economical, it is advantageous for the edge-lit type LED BLU to use a switching type circuit as shown in FIG. 1A.
FIG. 1A is a circuit diagram illustrating a related art LED driving integrated circuit (IC) using a boost circuit method.
Only several major pins of the LED driving IC are shown in FIG. 1A. The LED driving IC of FIG. 1A feeds a current flowing in an LED back thereto through a resistor Rs, compares the current with a reference current Iref corresponding to a current command, adjusts a switching duty of a first modulator M1 according to the comparison result, and controls the LED so that a voltage sensed by the resistor Rs accurately tracks the reference current Iref and thus a desired current flows in the LED. The most important problem of such a boost type circuit is that an output voltage infinitely increases if the LED is opened. Therefore, if a voltage sensed by an overvoltage protection (OVP) pin reaches a specific voltage, a latch type or auto-recovery type protection operates to turn off the first modulator M1 or both of the first modulator M1 and a second modulator M2.
FIG. 1B is a block diagram illustrating the related art LED driving IC of FIG. 1A.
An LED arranged above a BLU and an LED arranged under the BLU must be independently driven in a television (TV) or similar devices which support a 3-dimensional (3-D) mode. Therefore, two or more driving circuits are required. In this case, a system is constituted by repeatedly using a structure as shown in FIG. 1A.
FIG. 1C is a circuit diagram illustrating a related art driving system for driving a plurality of LED arrays.
Referring to FIG. 1C, OVP processing blocks of circuits are independently constituted and thus are arranged by the number of circuits. Therefore, the number of OVP pins which receive signals from the OVP processing blocks are too numerous.